1. Field of the Invention
The present invention relates to an ink-jet recording device and a recording control method thereof, and particularly relates to a configuration and method for adjusting the deviation of a recording position.
2. Description of the Related Art
A common ink-jet recording device includes a recording head including multiple recording elements which are integrated and arrayed for improving recording speed, an ink discharge unit in which multiple ink discharge orifices and liquid paths are integrated, and further the multiple recording heads corresponding to multiple colors.
FIG. 1 illustrates a configuration of an ink-jet printer unit at the time of recording on a surface of a recording sheet using the above-described recording head. In the drawing, reference numeral 101 denotes ink cartridges. The ink cartridges comprise ink tanks in which ink of four colors of black, cyan, magenta, and yellow is filled respectively, and a common recording head 102. FIG. 2 illustrates a situation in which discharge orifices are arrayed on this recording head from the Z direction, wherein reference numerals 201 and 202 denote multiple discharge orifices arrayed on the recording head 102. Returning to FIG. 1 again, reference numeral 103 denotes a sheet feeding roller, which rotates in the direction of an arrow in the drawing while suppressing a recording medium P along with spurs 104, and feeds the recording medium P in the sub-scanning direction which is the Y direction as necessary. Also, reference numeral 105 denotes a feeding roller, which performs feeding of the recording medium P, and also serves as a role for suppressing the recording medium P, as with the sheet feeding roller 103 and spurs 104. Reference numeral 106 denotes a carriage which supports, records, and also moves the four ink cartridges. The carriage stands ready at a home position (h), which is a position illustrated with a dotted line in the drawing, when performing no recording, or when performing recovery work of the recording head.
The carriage 106, which is positioned at the position (home position) illustrated in the drawing prior to start of recording, upon receiving a recording start command, discharges ink from the multiple discharge orifices 201 and 202 on the recording head 102 to perform recording while moving in the main-scanning direction which is the X direction. Upon recording for forming an image being completed, i.e., the carriage 106 reaching a recording medium end portion at the opposite side of the home position, the carriage returns to the original home position, and performs one-way recording again, which repeats recording in the X direction. Also, in order to perform high-speed printing, the carriage performs bi-directional recording, which performs recording from both of the +X direction serving as the outward direction and the −X direction serving as the homeward direction.
At this time, deviation sometimes occurs at the recording position of a dot to be discharged from the respective discharge orifice rows of the four colors, or the recording position of a dot to be discharged from both of the outward direction and the homeward direction. Also, the mounting accuracy of the recording head and manufacturing irregularities cause a leaning (slanting) as to the mains-scanning direction of the discharge orifice rows. Printing in a state having such misalignment may cause a leaning dot to be printed on a recording medium. Various techniques have been proposed to perform dot recording position adjustment (register adjustment) to correct such misalignment.
FIG. 2 illustrates two recording heads, a first recording head having an ink discharge orifice row A for discharging the black ink of the four-color ink described with FIG. 1, and a second recording head having an ink discharge orifice row B for discharging the cyan ink. The recording heads are each configured so as to have the number of ink discharge orifices L=12, and recording pixel density of 600 dpi based on the interval of the ink discharge orifices of 1/600 inch. The ink discharge orifice 201 represents the ink discharge orifice n12 of the ink discharge orifice row A, and similarly, the ink discharge orifice 202 represents the ink discharge orifice n1 of the ink discharge orifice row B. Also, the amount of discharge from the recording heads is arranged such that approximately 2-pl ink droplet per one droplet can be discharged, and the discharge frequency for discharging this ink droplet in a stable manner is 30 kHz, and the discharge speed thereof is approximately 20 m/sec. The speed of the carriage mounting this recording head in the main-scanning direction is approximately 25 inch/sec when recording ink droplets with an interval of 1200 dpi in the main-scanning direction.
The deviation of a recording position between the two discharge orifice rows is adjusted using the recording head 102. FIG. 34 illustrates check patterns for obtaining an adjustment value for adjusting the deviation of a recording position between the two rows of dots to be discharged from the outward direction of the ink discharge orifice row A and ink discharge orifice row B in FIG. 2, and FIG. 4 is an enlarged view of the check patterns corresponding with 0 through +2 in FIG. 34. On the outward course recording is performed by changing discharge timing from the ink discharge orifice row B on the basis of the recording position of a dot to be discharged from the ink discharge orifice row A. An arrangement is made wherein the discharge timing is slow in the + direction, and is fast in the − direction.
The resolution which can adjust this recording positional deviation is approximately 21 μm at 1200 dpi, and can adjust the deviation of a dot recording position within a range of seven-stage patterns of −3 through +3.
With respect to the check pattern corresponding to +1 in FIG. 4, black circles to be recorded by the ink discharge orifice row A, and white circles to be recorded by the ink discharge orifice wire B are overlapped to be disguised as one line, and the amount of deviation d2 in the X direction between the two rows is approximately 0 μm.
With respect to the check pattern corresponding to +2 in FIG. 4, the recording timing of the white circles to be recorded at the ink discharge orifice row B is 1200 dpi, which is slower than the black circles to be recorded at the ink discharge orifice row A by one pixel, and the amount of deviation d1 in the X direction between the two rows is approximately 21 μm. With respect to the check pattern corresponding to 0 in FIG. 4, the recording timing of the white circles to be recorded at the ink discharge orifice row B is 1200 dpi, which is faster than the black circles to be recorded at the ink discharge orifice row A by one pixel, and the amount of deviation in the X direction between the two rows is approximately 21 μm.
FIG. 35 is a flowchart for describing the above adjustment of the deviation of a recording position between the two rows of the ink discharge orifice row A and the ink discharge orifice row B.
First, in step 4601, the check patterns illustrated in FIG. 34 are recorded for obtaining an adjustment value for adjusting the deviation of a recording position between the two rows of the ink discharge orifice row A and the ink discharge orifice row B.
In step 4602, the number +1 is selected from the check patterns illustrated in FIG. 34, which corresponds with the check pattern having the least amount of deviation in the X direction between the two rows, for obtaining an adjustment value for adjusting the deviation of a recording position between the two rows of the ink discharge orifice row A and the ink discharge orifice row B.
In step 4603, the selected number +1 or a value associated with the selected number is stored in the EEPROM of the recording device main unit (nonvolatile memory, hereinafter referred to as EEPROM) as a recording position adjustment value. Recording is performed based on this stored recording position adjustment value. Description has been made in Japanese Patent Laid-Open No. 1995-40551 regarding the above recording position adjustment.
However, an ink-jet recording device to be employed for photographic printing realizes improvement of image quality by reducing the size of droplets or the like for the sake of further improvement of image quality. Consequently, manufacturing irregularities of recording heads, and the accuracy at the time of mounting a recording head on the recording device become important factors. Particularly, there has been demand for reduced leaning printing on a recording medium, which is caused by manufacturing irregularities and leaning in the rotational direction θ due to the mounting accuracy of a recording head described in FIG. 2, and elimination of the deviation of recording position.
FIG. 7 illustrates two recording heads having a different leaning in the rotational direction θ of the ink discharge orifice rows due to manufacturing irregularities as to the recording head described with FIG. 2, or the like.
The ink discharge orifice n1 of the ink discharge orifice row A is apart from the ink discharge orifice n12 by approximately 63 μm of 3 dots at 1200 dpi in the +X direction in FIG. 7. Also, the ink discharge orifice n1 of the ink discharge orifice row B is apart from the ink discharge orifice n12 by approximately 63 μm of 3 dots at 1200 dpi in the −X direction in FIG. 7.
FIG. 10 illustrates check patterns for obtaining an adjustment value for adjusting the deviation of a recording position between the two rows of dots to be discharged from the outward direction of the ink discharge orifice row A and ink discharge orifice row B in FIG. 7, and FIG. 11 is an enlarged view of the check patterns corresponding with −3 through −1 in FIG. 10.
On the outward course recording is performed by changing the discharge timing from the ink discharge orifice row B on the basis of the recording position of a dot to be discharged from the ink discharge orifice row A. An arrangement is made wherein the discharge timing is slow in the + direction, and is fast in the − direction.
Adjustment resolution is approximately 21 μm of 1200 dpi, and can adjust the deviation of a dot recording position within a range of seven-stage patterns of −3 through +3.
With regard to −2 which corresponds with a check pattern having the least amount of deviation of seven-stage patterns of −3 through +3 in FIG. 10, the amount of deviation d2 (shown in FIG. 11) in the X direction between the two rows of the black circles to be recorded at the ink discharge orifice row A and the white circles to be recorded at the ink discharge orifice row B is approximately 63 μm.
With regard to the check pattern −1 shown in FIGS. 10 and 11, the recording timing of the white circles to be recorded at the ink discharge orifice row B is 1200 dpi, which is slower than the black circles to be recorded at the ink discharge orifice row A by one pixel, and the amount of deviation d1 in the X direction between the two rows is approximately 84 μm.
With regard to the check pattern −3 shown in FIGS. 10 and 11, the recording timing of the white circles to be recorded at the ink discharge orifice row B is 1200 dpi, which is faster than the black circles to be recorded at the ink discharge orifice row A by one pixel, and the amount of deviation in the X direction between the two rows is approximately 84 μm.
As described above, with the recording head having no leaning θ such as FIG. 2, the least amount of deviation of a recording position is 0 μm, but on the contrary, with the recording head having the leaning θ illustrated in FIG. 7, even the least amount of deviation is 63 μm, and accordingly, the deviation of a recording position can be significant, resulting in a factor for deterioration of image.
FIG. 5B shows check patterns for obtaining an adjustment value for adjusting the deviation of a recording position due to the leaning in the rotational direction θ caused in the case of recording using the recording head in FIG. 7. Check patterns A are recorded on the outward course of the ink discharge orifice row A, and FIG. 6 is an enlarged view thereof. Check patterns B are recorded on the outward course of the ink discharge orifice row B, and FIG. 8 is an enlarged view thereof.
FIG. 9 illustrates divisions of an ink discharge orifice row to be performed at the time of adjustment of leaning printing in FIG. 5B. An ink discharge orifice group 2401 corresponds to the discharge orifices n1 though n6 of the discharge orifice row A and the discharge orifices n1 though n6 of the discharge orifice row B. An ink discharge orifice group 2402 corresponds to the discharge orifices n7 though n12 of the discharge orifice row A and the discharge orifices n7 though n12 of the discharge orifice row B. An ink discharge orifice group 2403 corresponds to the discharge orifices n1 though n4 of the discharge orifice row A and the discharge orifices n1 though n4 of the discharge orifice row B. An ink discharge orifice group 2404 corresponds to the discharge orifices n5 though n8 of the discharge orifice row A and the discharge orifices n5 though n8 of the discharge orifice row B. An ink discharge orifice group 2405 corresponds to the discharge orifices n9 though n12 of the discharge orifice row A and the discharge orifices n9 though n12 of the discharge orifice row B. Also, let us say that the reference is the ink discharge orifice group 2403 corresponding to the ink discharge orifices n1 through n4 of each ink discharge orifice row. In the case of dividing an ink discharge orifice row into two, recording is performed on the outward course by changing the discharge timing of the ink discharge orifice group 2402 as to the ink discharge orifice group 2401 including the ink discharge orifice group 2403 serving as the reference. An arrangement is made such that the discharge timing is slow in the + direction, and is fast in the − direction.
In the case of dividing an ink discharge orifice row into three, recording is performed on the outward course by changing the discharge timing of the ink discharge orifice group 2404 as to the ink discharge orifice group 2403 serving as the reference. Similarly, recording is performed by further changing the discharge timing of the ink discharge orifice group 2405 as to the ink discharge orifice group 2403 serving as the reference. An arrangement is made such that the discharge timing is slow in the + direction, and is fast in the − direction.
Number-of-divisions adjustment resolution is approximately 21 μm of 1200 dpi, and can adjust the deviation of a dot recording position within a range of five-stage patterns of −2 through +2.
With respect to the pattern corresponding to 0 illustrated in FIG. 6, recording is performed by setting the discharge timing from all of the ink discharge orifices to the same discharge timing without dividing the ink discharge orifice row A, and the amount of deviation of a recording position is approximately 84 μm. With respect to the pattern corresponding to +1 in FIG. 6, the ink discharge orifice row A is divided into two, the recording timing at the ink discharge orifice group 2402 is 1200 dpi, which is slower than the ink discharge orifice group 2401 including the ink discharge orifice group 2403 serving as the reference by one pixel, and the amount of deviation d4 of the recording position of the ink discharge orifice row A is approximately 63 μm. With respect to the pattern corresponding to +2 in FIG. 6, the ink discharge orifice row A is divided into three, the recording timing at the ink discharge orifice group 2404 is 1200 dpi, which is slower than the ink discharge orifice group 2403 serving as the reference by one pixel, and further the recording timing at the ink discharge orifice group 2405 is 1200 dpi, which is slower than the ink discharge orifice group 2403 serving as the reference by two pixels. The amount of deviation d5 of the recoding position of the ink discharge orifice row A at this time is approximately 42 μm. With respect to the pattern corresponding to −1 in FIG. 6, the ink discharge orifice row A is divided into two, the recording timing at the ink discharge orifice group 2402 is 1200 dpi, which is faster than the ink discharge orifice group 2401 including the ink discharge orifice group 2403 serving as the reference by one pixel, and the amount of deviation d2 of the recording position of the ink discharge orifice row A is approximately 105 μm. With respect to the pattern corresponding to −2 in FIG. 6, the ink discharge orifice row A is divided into three, the recording timing at the ink discharge orifice group 2404 is 1200 dpi, which is faster than the ink discharge orifice group 2403 serving as the reference by one pixel, and further the recording timing at the ink discharge orifice group 2405 is 1200 dpi, which is faster than the ink discharge orifice group 2403 serving as the reference by two pixels. The amount of deviation d2 of the recoding position of the ink discharge orifice row A at this time is approximately 126 μm.
With respect to the pattern corresponding to 0 illustrated in FIG. 8, recording is performed by setting the discharge timing from all of the ink discharge orifices to the same discharge timing without dividing the ink discharge orifice row B, and the amount of deviation d3 of the recording position is approximately 84 μm. With respect to the pattern corresponding to +1 in FIG. 8, the ink discharge orifice row B is divided into two, the recording timing at the ink discharge orifice group 2402 is 1200 dpi, which is slower than the ink discharge orifice group 2401 including the ink discharge orifice group 2403 serving as the reference by one pixel, and the amount of deviation d4 of the recording position of the ink discharge orifice row B is approximately 105 μm. With respect to the pattern corresponding to +2 in FIG. 8, the ink discharge orifice row B is divided into three, the recording timing at the ink discharge orifice group 2404 is slower than the ink discharge orifice group 2403 serving as the reference, and further the recording timing at the ink discharge orifice group 2405 is 1200 dpi, which is slower than the ink discharge orifice group 2403 in FIG. 24 serving as the reference by two pixels. The amount of deviation d5 of the recoding position of the ink discharge orifice row B at this time is approximately 126 μm. With respect to the pattern corresponding to −1 in FIG. 8, the ink discharge orifice row B is divided into two, the recording timing at the ink discharge orifice group 2402 is 1200 dpi, which is faster than the ink discharge orifice group 2401 serving as the reference by one pixel, and the amount of deviation d2 of the recording position of the ink discharge orifice row B is approximately 63 μm. With respect to the pattern corresponding to −2 in FIG. 8, the ink discharge orifice row B is divided into three, the recording timing at the ink discharge orifice group 2404 is 1200 dpi, which is faster than the ink discharge orifice group 2403 serving as the reference by one pixel, and further the recording timing at the ink discharge orifice group 2405 is 1200 dpi, which is faster than the ink discharge orifice group 2403 in FIG. 24 serving as the reference by two pixels. The amount of deviation d1 of the recoding position of the ink discharge orifice row B at this time is approximately 42 μm.
FIG. 15A is a flowchart for describing adjustment of a recording positional deviation within an ink discharge orifice row using the recording head in FIG. 7. First, in step 1501, the check patterns A are recorded for obtaining an adjustment value for adjusting a recording positional deviation in the θ direction within the ink discharge orifice row A.
In step 1502, the number of +2 is selected wherein the amount of deviation at the recording position is the least, i.e., a small deviation as to the main-scanning direction from the check patterns A in FIG. 5A for obtaining an adjustment value for adjusting a recording positional deviation in the θ direction within the ink discharge orifice row A. In step 1503, the selected +2 is stored in the EEPROM of the recording device main unit as a recording position adjustment value within the ink discharge orifice row A. In step 1504, the check patterns B are recorded for obtaining an adjustment value for adjusting a recording positional deviation in the θ direction within the ink discharge orifice row B. In step 1505, the number of −2 is selected wherein the amount of deviation at the recording position is the least, i.e., a small deviation as to the main-scanning direction from the check patterns B in FIG. 5A for obtaining an adjustment value for adjusting a recording positional deviation in the θ direction within the ink discharge orifice row B. In step 1506, the selected −2 is stored in the EEPROM of the recording device main unit as a recording position adjustment value within the ink discharge orifice row B.
FIG. 12 is check patterns for obtaining an adjustment value for adjusting a recording positional deviation between two ink discharge orifice rows recorded on the outward course upon which the recording position adjustment values stored in the EEPROM within the ink discharge orifice row A and within the ink discharge orifice row B in FIG. 7 are reflected. FIG. 13 is an enlarged view of 0 through +2 in FIG. 12.
On the outward course recording is performed by changing the discharge timing from the ink discharge orifice row B on the basis of the recording position of a dot to be discharged from the ink discharge orifice row A. An arrangement is made wherein the discharge timing is slow in the + direction, and is fast in the − direction.
Adjustment resolution is approximately 21 μm of 1200 dpi, and can adjust the deviation of a dot recording position within a range of seven-stage patterns of −3 through +3.
With respect to the pattern corresponding to +1 illustrated in FIG. 13, black circles to be recorded by the ink discharge orifice row A, and white circles to be recorded by the ink discharge orifice wire B are overlapped, and the amount of deviation d2 in the X direction between the two rows is approximately 42 μm. With respect to the pattern corresponding to +2 in FIG. 13, the recording timing of the white circles to be recorded at the ink discharge orifice row B is 1200 dpi, which is slower than the black circles to be recorded at the ink discharge orifice row A by one pixel, and the amount of deviation d1 in the X direction between the two rows is approximately 63 μm. With respect to the pattern corresponding to 0 in FIG. 13, the recording timing of the white circles to be recorded at the ink discharge orifice row B is 1200 dpi, which is faster than the black circles to be recorded at the ink discharge orifice row A by one pixel, and the amount of deviation d3 in the X direction between the two rows is approximately 63 μm.
Now, FIG. 15B is a flowchart for describing adjustment of a recording positional deviation between ink discharge orifice rows using the recording head in FIG. 7. In step 1507, the check patterns C in FIG. 12 are recorded for obtaining an adjustment value for adjusting a recording positional deviation between the two rows of the ink discharge orifice row A and the ink discharge orifice row B in a state in which the recording positions within the respective ink discharge orifice rows are adjusted based on the recording position adjustment values within the ink discharge orifice row A and the recording position adjustment values within the ink discharge orifice row B for adjusting the recording positions in the θ direction. In step 1508, the number of +1 wherein the amount of deviation in the X direction between the two rows is the least is selected from the check patterns C in FIG. 12 for obtaining an adjustment value for adjusting the deviation of a recording position between the two rows of the ink discharge orifice row A and the ink discharge orifice row B.
In step 1509, the selected +1 is stored in the EEPROM of the recording device main unit as a recording position adjustment value between the two rows of the ink discharge orifice row A and the ink discharge orifice row B. Recording is performed based on this stored recording position adjustment value. As described above, deterioration of an image due to a recording positional deviation caused by manufacturing irregularities of recording devices and recording heads, and mounting irregularities of a recording head can be reduced.
However, with this method, first, it is necessary to obtain a recording position adjustment value for adjusting a recording positional deviation within the ink discharge orifice row for each ink discharge orifice row. Next, in a state in which a recording positional deviation within the ink discharge orifice row is adjusted using the adjustment value, a recording positional deviation between ink discharge orifice rows is adjusted. Accordingly, it is necessary to perform recording position adjustment in two stages, which causes very poor usability.